Based on the Following Data,a Forecaster Used Simple Exponential Smoothing $$\begin{array} { c c } \text { Time } & \text { Demand } \\1 & 17 \\2 & 21 \\3 & 19 \\4 & 23 \\5 & 18\end{array}$$

Essay

Based on the following data,a forecaster used simple exponential smoothing and determined the following: S₀ = 19,S₁ = 18.6,S₂ = 19.08,S₃ = 19.064,S₄ = 19.851 and S₅ = 19.481. $$\begin{array} { c c } \text { Time } & \text { Demand } \\1 & 17 \\2 & 21 \\3 & 19 \\4 & 23 \\5 & 18\end{array}$$
-Calculate the average forecast error.